Locating device for temperature compensated parallax barrier supporting system

ABSTRACT

Cooperating means formed between a temperature-compensating member having an expansion loop and a sidewall of a parallax barrier are provided to insure centering of the loop within a preformed opening in the barrier sidewall. The cooperating means comprise protruding portions and matching receiving openings therefor, either of which may be formed on either member with the mating portion formed on the other member.

United States Patent Benedict F. Vitale Auburn, N.Y.

Dec. 23, 1968 Apr. 6, 1971 Sylvania Electrics Products Inc.

Inventor Appl. No. Filed Patented Assignce LOCATING DEVICE FOR TEMPERATURE COMPENSATED PARALLAX BARRIER SUPPORTING SYSTEM 1 Claim, 5 Drawing Figs.

US. Cl 313/85, 313/292 Int. Cl I101j 29/02, H0lj 29/32, HOlj 29/06 Field ofSearch 313/85 (S),

92(B),92(PDF) [56] References Cited UNITED STATES PATENTS 3,330,980 7/1967 Shrader 313/855 3,370,194 2/1968 Schwartz et all. 313/928 3,449,61 1 6/1969 Schwartz et al. 313/92BX 3,449,612 6/1969 Zachrich 313/855 Primary Examiner-Robert Segal Attorneys-Norman J. OMalley, Cyril A. Krenzer and William H. McNeill ABSTRACT: Cooperating means formed between a temperature-compensating member having an expansion loop and a sidewall of a parallax barrier are provided to insure centering of the loop within a preformed opening in the barrier sidewall. The cooperating means comprise protruding portions and matching receiving openings therefor, either of which may be formed on either member with the mating portion formed on the other member.

Patented Aprih 6, 1111 2 Sheets-Sheet 1 INVENTOR. BENEIWCT E WTMLE ATTORNEY Patented April 6, 1971 2 Sheets-Sheet 2 INVENTOR. aemamcr F. WTMJE ATTORNEY EGCATIING DEVICE EOII TEMPERATURE COMIENSATED IPAIRALLAX BARRIER SUPPORTING SYSTEM BACKGROUND OF THE INVENTION This invention relates to color cathode ray tubes and more particularly to temperature compensated, parallax barrier supporting systems for use therein.

In conventional color cathode ray tubes in use today, the light-emitting screen is comprised of a pattern of differentcolored light-emitting phosphors. Positioned behind the screen; i.e., between the screen and the electron source which energizes the phosphors to luminescence, is a parallax barrier which aids in color selection. The barrier is releasably mounted by means of springs within the tube and is provided with a foraminated pattern which is in accurate registry with the phosphor pattern on the screen. During operation of the tube the barrier enlarges due to the heat generated therein by the impingement of the electron beams thereon. This increase in size has, in the past, caused some loss of registration in the tube resulting in an improper color balance. To counteract this effect, the supporting springs have been attached to the barrier sidewalls through the intermediary of a bimetallic ele ment or baseplate which is provided with an expansion loop or hinge. The bimetallic baseplate utilizes the heat generated in the barrier to change the position of the barrier during operation of the tube in a controlled manner to substantially maintain the desired registration. For a more detailed operation of the bimetallic device, reference may be had to US. Pat. No. 3,330,980.

The expansion loop on this element, when installed on a parallax barrier, projects inwardly toward the center of the tube. To accommodate this projection a slot, larger in size than the loop, is provided in the barrier sidewall. To insure proper operation of the device, the loop must be centered within the opening to insure its nonbinding expansion and contraction. In the past this has been a tedious and time-consuming hand operation with an operator attempting to visually center the device and maintain it in position while it was welded or otherwise permanently fixed in position. Besides the disadvantages named above, there was no particular guarantee of success.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of the invention to enhance the operation of color cathode ray tubes employing these devices.

It is another object of the invention to insure nonbinding operation of these devices.

It is yet another object of the invention to remove operatorerror as a factor in the installation of such devices.

These and other objects are accomplished in one aspect of the invention by the provision, within a color cathode ray tube of the class described, of cooperating baseplate locating means formed on the baseplate and the sidewall of the paral lax barrier to achieve substantially central location of an expansion loop within a preformed opening whereby its nonbinding action during operation is insured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a diagrammatic sectional view of a typical color cathode ray tube;

FIG. 2 is a partial perspective view illustrating one embodiment ofthe invention;

FIG. 3 is a partial perspective view illustrating another embodiment of the invention;

FIG. 4 is a partial perspective view illustrating yet another embodiment of the invention; and

FIG. 5 is a partial perspective view illustrating still another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the the abovedescribed drawings.

Referring now to the drawings with; greater particularity, there is shown in FIG. I a color cathode ray tube I0 having a faceplate I2 with a patterned phosphor screen I4 disposed on the interior surface thereof. A peripheral sidewall 16 extends from faceplate I2 and joins a substantially funnel-shaped body I8. The narrow end of the funnel terminates in a cylindrical neck 20 which encloses an electron source 22, which is typically in the form of three electron guns. A parallax barrier 24 is releasably mounted within the tube adjacent the screen. The tube is evacuated as is conventional in the art and is provided with suitable leads (not shown) for making electrical connection to the proper components.

The parallax barrier 24 comprises a relatively fragile apertured portion 26 which is fixed at its peripheral edge to a relatively rigid frame 28. The frame provides the parallax barrier sidewalls 30 to which the supporting springs are attached. The configuration of the apertures in portion 26 may be either substantially circular or rectangular depending upon the screen pattern.

Referring now to FIG. 2 there is shown a section of parallax barrier 24 together with one of its spring support systems 32. Normally, in current tubes, either three or four such systems are utilized; however, since they are all substantially identical, only one is shown here. The spring support system comprises a bimetallic baseplate 34 having upper and lower sections 36 and 38 respectively, joined together by an expansion loop 40 which projects from the plane of the baseplate inwardly toward the center of the tube I0. To accommodate the loop 40 there is provided a substantially rectangular loop-receiving opening 42 formed in sidewall 30.

A leaf spring 44 is attached to upper portion as of the baseplate 34 and projects outwardly therefrom. The free end of spring 44 is provided with an aperture 46 for engaging a stud 4% which is provided on the interior surface of peripheral wall I6.

In order for the loop to function properly, opening 42 must be large enough to provide for freedom of movement thereof during operation. Further, even when the opening is sufficiently large, care must be taken to assure that the loop is properly centered therein and is not binding against one of the edges of the opening.

To insure this desirable result, there is provided cooperating baseplate locating means formed on the baseplate 34 and the sidewall 30. In the embodiment shown in FIG. 2 the locating means comprises a substantially elongated protrusion 50 ex tending from the plane of the baseplate 34 toward the center of the tube. A matchingly configured second opening 52 is formed in sidewall 30 to receive protrusion 50 with a substantially snug fit. The second opening 52 should be just enough larger than protrusion 50 to allow for easy entry thereinto without allowing any room for slop, since this would permit the baseplate 34 to be misaligned. The actual amount of tolerance allowed between the second opening 52 and the protrusion 50 will depend in part upon the materials being utilized and the cost factor willing to be borne by the tube producer.

An alternate embodiment of the locating means is shown in FIG. 3 wherein it comprises at least two protuberances 54 and 56 respectively which, in this instance, are shown as being formed on barrier sidewall 30. Matching openings 5% and 60 are provided in baseplate 34. Obviously, the conditions may be reversed and the protuberances may be formed on the baseplate with the openings in the sidewall. In the instant case the protuberances are shown as being cylindrical; however, it is to be understood that this is illustrative only and that other configurations may be employed.

Another embodiment of the invention is illustrated in FIG. 4 wherein the locating means comprises a single, substantially elongated protrusion 62 extending outwardly from the plane of sidewall 30. A matching opening 64 is provided in baseplate 34. The protrusion 62 may be punched from the sidewall 30 or it may be an additional member welded thereon.

A still further embodiment is shown in FIG. wherein'the locating means comprises an adjacent pair of edges of baseplate 34; for example, 66 and 68 respectively. The complimentary locating means on the sidewall then takes the form of a substantially L-shaped bracket 70 having a leg 72 and a leg 74. In this embodiment, fitting the edge 66 against leg 74 and edge 68 against leg 72 will provide the desired alignment.

In each of the above-described embodiments, after the cooperative coupling of the locating means, the baseplate is permanently afiixed in position on the sidewall 30 by means of welding or other suitable method.

Thus, it will be seen that there is provided by this invention novel means for enhancing the operation of color cathode ray tubes employing bimetallic, temperature-compensating devices. Nonbinding action of the expansion loop is insured and the factor of operator-error is removed.

While there have been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

We claim:

I. A color cathode ray tube having an envelope and a patterned, mosaic screen therein; a parallax barrier mounted within said tube adjacent said screen comprised of a relatively fragile apertured portion and a relatively heavy frame having a wall, said apcrtured portion being attached at its peripheral edge to said wall of said frame, each of the apertures in said barrier being aligned with particular areas of said mosaic screen; said mounting for said barrier in said tube including means for maintaining said alignment during tube operation, said last-named means comprising: a plurality of temperature compensating mounting members spaced about said wall of said frame each comprising a bimetallic baseplate formed from contiguous materials having different thermal coefficients of expansion and being formed to have a protruding extending loop extending therefrom, said loop being responsive to temperature changes within said tube and being formed between first and second ends of said baseplate; means for attaching a first end of each of said baseplates to said wall of said frame an opening formed in said wall of said frame to receive said loop; cooperating baseplate locating means formed on said first end of said baseplate and said wall to achieve substantially central location of said loop within said opening whereby its nonbinding action is insured; said cooperating baseplate locating means comprising an elongated protrusion having tapered sides extending from the plane of one of said baseplate and barrier sidewall and a second opening formed in the other of said baseplate and barrier sidewall having sides formed to achieve a snug fit of said elongated protrusion therein a like plurality of spaced studs projecting internally of said tube attached to said envelope; and a like plurality of leaf springs each having one attached to one of said studs and the other end affixed to one of said second ends of one of said baseplates. 

1. A color cathode ray tube having an envelope and a patterned, mosaic screen therein; a parallax barrier mounted within said tube adjacent said screen comprised of a relatively fragile apertured portion and a relatively heavy frame having a wall, said apertured portion being attached at its peripheral edge to said wall of said frame, each of the apertures in said barrier being aligned with particular areas of said mosaic screen; said mounting for said barrier in said tube including means for maintaining said alignment during tube operation, said last-named means comprising: a plurality of temperature compensating mounting members spaced about said wall of said frame each comprising a bimetallic baseplate formed from contiguous materials having different thermal coefficients of expansion and being formed to have a protruding extending loop extending therefrom, said loop being responsive to temperature changes within said tube and being formed between first and second ends of said baseplate; means for attaching a first end of each of said baseplates to said wall of said frame an opening formed in said wall of said frame to receive said loop; cooperating baseplate locating means formed on said first end of said baseplate and said wall to achieve substantially central location of said loop within said opening whereby its nonbinding action is insured; said cooperating baseplate locating means comprising an elongated protrusion having tapered sides extending from the plane of one of said baseplate and barrier sidewall and a second opening formed in the other of said baseplate and barrier sidewall having sides formed to achieve a snug fit of said elongated protrusion therein a like plurality of spaced studs projecting internally of said tube attached to said envelope; and a like pluralIty of leaf springs each having one attached to one of said studs and the other end affixed to one of said second ends of one of said baseplates. 